置信域方法（Trust-region methods）又称为信赖域方法，它是一种最优化方法，能够保证最优化方法总体收敛。

置信域方法的历史可以追溯到Levenberg(1944)，Marquardt(1963)，Goldfeld，Quandt and Trotter(1966)，但现代置信域方法是Powell(1970)提出来的。他明确提出了置信域子问题，接受方向步的准则，校正置信域半径的准则，及收敛性定理。这些措施使置信域方法比线搜索方法具有更大的优越性。

Trust region is a term used in mathematical optimization to denote the subset of the region of the objective function that is approximated using a model function (often a quadratic). If an adequate model of the objective function is found within the trust region then the region is expanded; conversely, if the approximation is poor then the region is contracted. Trust region methods are also known as restricted step methods.